A VPN has a number of uses, most often by large companies so employees can use the company intranet when traveling. They are also used to hide a computer users identity; basically your browser will be routed through a proxy server, thereby providing you with an alternative ip address. It's not sinister (normally)! It's very useful for puerile who travel but need geographically sensitive ip addresses to access content from their own country say. There are many providers of VPN's, a monthly fee is usually payable, there are some providers on Amazon for instance. If you got a uk one, it would make your tablet look as though it's in the UK, the nexus 7 does have a VPN setting facility.
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